I. Field of Use
The present invention relates to a method and a device for processing carbon bodies. In particular, the present invention concerns the processing of grooves or slots in calcinated carbon bodies.
II. Description of Related Art
In aluminum electrolysis using the so-called Hall-Héroult method with prebaked anodes, gas bubbles are created at the wearing (or consumable) surfaces of the anodes (mainly underneath them).
The presence of a gas layer means that the electrical resistance towards the bath increases, resulting in reduced current efficiency. In accordance with the prior art, solutions are proposed that involve ducts or grooves being created in the wearing surfaces of the anodes in order to drain the gas away, conduct it out of the bath and collect it in a degassing system. The prior art also proposes creating longitudinal grooves in the cathode carbon in order to be able to incorporate electrically conductive cathode rods.
Grooves in carbon bodies can be formed or preformed when the bodies are in a green state, i.e. before calcination or baking. One disadvantage of this is that the geometry of the grooves may be changed during handling and baking on account of creep or external mechanical stress. Such preforming may result in density gradients in the anode and rejects in the process. It may therefore be necessary to process (calibrate) the grooves so that they have the correct geometry.
The prior art also proposes processing holes in calcinated carbon bodies using mechanical equipment comprising a milling head that is similar to a drill bit for drilling bedrock, see EP 0922516. However, this equipment is not appropriate for creating slots with an extent equivalent to that of the carbon body, as it generally rotates around an axis perpendicular to the surface of the body and will suffer from capacity restrictions in connection with such a task.
US 2003/0075163 A1 describes a saw blade with inserts partly of polycrystalline diamond and partly of a carbide material. The blade is suitable for sawing a composite material comprising cement, ground sand and cellulose fiber, which is a material with completely different properties and which therefore also requires a different processing process than the present material.